1. Field of the Invention
The present invention relates to a surface texture measuring apparatus and method measuring a surface texture of an interior wall of a measurable object using a non-contact-type measurement sensor.
2. Description of Related Art
Conventionally, a surface texture measuring apparatus measuring a surface texture of a measurable object has been used. For example, a surface texture measuring apparatus disclosed in Japanese Patent Laid-open Publication No. 2006-064512 detects a change in position of unevenness on a surface of a measurable object to measure an internal diameter and an external diameter of the measurable object.
In recent years, there has been a demand for automatic measurement of a detailed surface texture of an interior wall of a cylinder portion of a measurable object. A method has been proposed in which a measurement sensor measuring the interior wall without contact is rotated within the cylinder portion and the surface texture of the interior wall is measured. However, this measurement method performs measurement on the assumption that the cylinder portion of the measurable object is a perfect circle, but in some cases a real cylinder portion may not be a perfect circle. In such cases, a distance between the measurement sensor and the interior wall is not constant and therefore the interior wall cannot be measured with a high degree of accuracy, as compared to cases where the cylinder portion is a perfect circle.